MXPA97008653A - Superdispersable thickening composition for aqueous systems and a thickening method of those aqua systems - Google Patents

Abstract

An improved thickener composition for an aqueous system including latex paints and coatings is disclosed. The substantially anhydrous composition comprises in specific ratios a solid thickener polymer, and one or more surfactants. The solid thickener polymer includes associative thickeners. The associative thickener polymers include polyurethanes, polyesters, poly-acrylamides, modified hydroxyethyl celluloses, soluble alkali emulsions and other chemicals. Specific surfactants used include dialkyl sulfosuccinates, alkyl sulphates, alpha olefin sulphonates, and sulfates of ethoxylated alcohols.

Description

SUPERDISPERSABLE THICKENING COMPOSITION FOR AQUEOUS SYSTEMS AND A THICKENING METHOD AQUEOUS SYSTEMS BACKGROUND OF THE INVENTION The invention described herein includes improved thickener compositions, usually referred to as rheological additives, viscosity modifiers or thixotropes, used to impart rheological and viscous modification properties to a wide range of water or liquid based systems. . In many commercial applications a thickening chemical such as polyurethane polymer is added to an aqueous system, for example in latex paints, to change or modify the rheological properties of the system. It has been proven that rheological additives of the solid powder type are difficult to mix or disperse in most aqueous systems. The dispersion of these products in latex paints, coatings and other water-based systems is particularly difficult to dissolve. In view of these difficulties, these solid additives have been disapproved and have not reached or approached their full market potential. To avoid problems of dispersion, some manufacturers have mixed their polymeric powder in water and volatile organic liquids so that in this way "a liquid flowable rheological product is produced, which can then be emptied into aqueous paints, inks and coatings. however, they have recently made the use of such volatile organic liquids less acceptable, and that these liquid thickener compositions have themselves been disapproved.In addition, the use of organic liquids and water, which do not provide active rheological properties, increase the weight and volume of the thickeners, which adds considerably to the costs of shipping, transportation and packaging.The liquid products require non-porous containers and the additional cost of transportation, especially when exporting these products, has proved to have many disadvantages The present invention includes the discovery that a substantially anhydrous mixture or a compound of a surfactant, preferably in the form of a powder, together with a solid polymeric thickener, defined hereinafter, constitutes a product which can easily be dispersed in water-based systems. It has been found that a wide variety of surfactants are effective. The mixed inventive product results in a thickener composition with an equal or improved viscosity and thickening properties, and at the same time adverse impacts to the environment are avoided due to the vapor emissions of volatile organic carriers and the additional transportation costs of the carriers. now unnecessary fluids. Description of the prior art It has been known in the art for many years that using various materials as rheological additives for, among other rheological properties, will modify the viscosity of aqueous systems. Aqueous systems include both water based and latex emulsion based paints and coatings, inks, construction materials, cosmetics and wood inks. Depending on the composition of the aqueous system, products made with these thickeners can be useful as decorative coatings, paper coatings for magazines, cosmetics and personal care articles, adhesives and sealants, numerous types of tubs, fluids for drilling oil wells , building compounds including binding compounds, and the like.

Natural polymers, modified natural and synthetic of various types, have been used as rheological additives. Natural thickeners include mineral clays, casein and alginates, including vegetable-based gums, such as guar gum. Modified natural thickeners include products that use woody plants as their base, such as cellulosic products, including methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and carboxymethyl cellulose, such products, natural and natural modified, vary widely in their thickening efficiency and in their properties of viscosity modification, flow and leveling.

Since the 1950's, synthetic polymeric thickeners have taken on increasing importance, particularly in the control of the viscosity of latex and aqueous emulsion paints and coatings. Synthetic polymeric thickeners are defined to include modified natural products. Synthetic polymeric thickeners serve several functions in these aqueous systems. When the term, "aqueous systems", is used in this application, it is intended to include latex paints and coatings, as well as latex inks.

In latex and other aqueous paints and coatings, the rheological additive provides improved stability and pigment suspension, and improves the properties use and application. In cosmetics and personal care items, such additives improve the body, texture, softness and silkiness, making the product more acceptable and aesthetically pleasing to sophisticated buyers. In oil drilling fluids, the use of a synthetic thickener improves the suspension of the well bore cuts, allowing stopping without the precipitation of such cuts, and in this way prolonging the useful life of the auger head and the drill bit. auger.

Synthetic polymeric rheological thickeners include various acrylic polymers and maleic anhydride copolymers. Two patents granted to Rheox Inc., the assignee of the present invention, describe a family of solid polyurethane thickener compositions, which is still sold under the trade designation or trade name of RHEOLATE. These U.S. Patent Nos. 4,499,233 and 5,023,309 further describe these synthetic polymeric thickeners as the reaction product of polyisocyanates, polyether polyols and modifying agents (which contain pendent internal hydrophobic groups and at least two active hydrogen groups) terminated by an agent chemical coroner at the end.

Another synthetic polymeric thickener widely used in commercial paints and commercial coatings is a low molecular weight polyurethane characterized by hydrophobic groups interconnected by hydrophilic polyether groups, and which is disclosed in U.S. Patent Nos. 4,079,028 and 4,155,892. A similar type of synthetic polymeric thickener is a water-soluble thermoplastic organic polymer having a number of monovalent hydrophobic groups incorporated in the inner part of the polymer molecule. U.S. Patent Nos. 4,496,708 and 4,426,485, issued to the Carbide Union Corporation, describe such thickeners as water soluble polymers containing pendent internal hydrophobic groups separated from the uncoated end of the polymer by the polyether units. The BASF Corporation has been granted a number of patents which disclose polyether rheological additives for aqueous systems obtained by crowning a straight-chain polyoxyalkene compound derived from ethylene oxide and at least some other lower alkylene oxide (a compound of polyoxyalkylene initiated with an initiator containing active hydrogen, disclosed as an example) with an alpha olefin oxide group. See, for example, U.S. Patent Nos. 4,288,639, 4,354,956 and 4,904,466. U.S. Patent Nos. 4,310,436 and 4,709,099 to BASF Corporation disclose covalent bond polyesters, polyester urethanes, and polyether alpha olefins as well as a variety of other types of polymers used as synthetic polymeric thickeners.

Many of the synthetic polymeric rheological additives described above have often been referred to by the term "associative" or thickener rheological additives. The mechanism by which such associative thickeners work probably involves "associations" (meaning widely interactions of some physical or chemical type) between the hydrophobic species in the molecules of the polymer thickener and other hydrophobic surfaces, either in the polymer molecules thickener or in the the molecules of the components contained in the system to be thickened. Different commercial types of associative thickeners include polyurethanes, hydrophobically modified alkali soluble emulsions, hydrophobically modified celloics and hydrophobically modified polyacrylamides.

The molecular weight of these associative thickeners, which can also be referred to as synthetic water soluble polymer, is high enough to impart desired rheological properties to the aqueous thickener-containing composition. Advantageously, the water-soluble polymer operates in such a way that a solution containing up to 2-3 weight percent of the polymer will exhibit a viscosity of at least about 50 g / cm * sec, preferably at least 150 g / cm * sec. gr / cm * sec, and more preferably at least 200 gr / cm * sec (as measured in a viscometer with an axis of number 3 at 10 rpm at 25 ° C).

As explained above, a variety of polymeric materials can be used as water-soluble rheology polymers, including cellulose ethers, polyacrylamides, sulfonated polystyrenes, acrylic acid copolymers, hydroxypropylated guar gum and the like. The choice of the particular water-soluble polymer depends basically on the compatibility of such polymer with the other components of the thickener composition containing the thickener, and on the end use of the aqueous system.

It has been found that levels of rheological thickener polymeric additive ranging from 0.1% to about 15%, based on the total weight of the system to be thickened are useful. As a general class, associative thickeners provide a combination of properties not found in any other single class of known aqueous thickeners. These are generally non-ionic, and in many cases they are viscosity improvers in a highly efficient sense even when they have molecular weights only within the middle range. They have stability in water and most are not sensitive to biodegradation.

Associative thickeners can also be defined as molecules that contain hydrophobic clusters located or dispersed through a hydrophilic backbone. The hydrophobic parts cause the association of, either with themselves or by the association of hydrophobic groupings contained in the various ingredients commonly found in aqueous paints, coatings and inks. Typical main chain polymers include polyurethanes, polyethers and starch type molecules. They are versatile in that both thicken virtually unlimited types of aqueous systems, and also impart many auxiliary beneficial properties. For example, as additives for textile binder compositions, they can soften rather than harden the fabric or fabric. In latex paints, they not only thicken but also provide superior flow and leveling properties, and give excellent viscosity control under both high and low stress conditions.

Improvement in flow or leveling was observed, compared to many products of the prior art, usually accompanied by an increase in viscosity, when the appropriate additive, selected from those described herein, was dispersed in any aqueous or latex system, or in grids . The beneficial effects are more visible in coating compositions of relatively low pigmentation, or where pigmentation is completely absent.

Such additives often find the most extensive use in semi-gloss or extremely expensive latex paints compositions.

Water-soluble thickeners for aqueous systems are prepared and sold and used in a solid, dry form; the powder form is the most common. The dust associated with the incorporation of dry polymers into the industrial environment presents similar problems of conventional handling of the material, such as those encountered with other types of dry particles. In addition, when added to aqueous systems the solid polymers in powder tend to agglomerate to form lumps. The agglomeration can be reduced in many cases by adding the solid polymer to the aqueous systems slowly with agitation. In other cases, the solid thickener is first portioned in water to form a water / polymer mixture, and then the dispersion is allowed to "settle" into the aqueous system to be thickened. However, such slow dissolution can affect the efficiency of specific manufacturing operations.

It has been proven that water-soluble solid polymers have particular difficulty in incorporating into industrial paint manufacturing processes, because they often require long periods of time to dissolve. Both in aqueous solutions and more particularly in formulations comprising other chemicals and ingredients, prolonged periods of agitation and aging are necessary before the proper viscosity and dispersion is obtained. For the reasons mentioned above, manufacturers have sought a simple, quick and effective way to mix water soluble solid polymers in their aqueous systems. Due to this search, many associative commercial thickeners are currently sold as pourable liquid "concentrates". Such commercial concentrates, in liquid form for latex paints and other compositions, usually include taking the solid polymer and preparing a thickener mixture as a mixture of water and a water miscible organic solvent such as diethylene glycol monobutyl ether. (also known as butyl carbitol) or propylene glycol or ethylene. The addition of this organic co-solvent lowers the viscosity of the polymer in water to provide ease in handling, and allows an efficient level of activity in the final product. The water-miscible solvent selected for such commercial compositions to date has been almost exclusively an organic solvent. For example, commercial polymer rheology additives for water-containing paint systems, designated Reox RHEOLATE 255.278, and 300, are currently sold as liquids in a thickener / butyl carbitol / water mixture.

Although "liquid" rheological additives are used at relatively low levels, as indicated above, the use of an organic volatile co-solvent in such rheological additives contributes to the thickening of the volatile organic content, called VOC, of aqueous systems. Reducing the VOC of water-containing systems, including major construction and painting systems, without adversely affecting the other properties of the systems, is currently a very active research topic throughout the world, particularly in the United States.

The previously cited Union Carbide patent, US Patent No. 4,426,485 discloses a solvent / water mixture for a polymer thickener composition of appropriate amounts of polymer, the organic solvent of diethylene glycol monobutyl ether, and water. This type of organic solvent evaporates after the paints or coatings containing it are applied, and enters the atmosphere during the drying of such aqueous compositions. Similar evaporation occurs after the application of inks, bonding compounds and sealants, among other thickened substances.

It has become very important in combating atmospheric pollution to remove organic pollutants, including vapors released in the course of industrial and architectural painting and in the manufacture of painted and coated articles, such as automobiles and furniture. Such inorganic vapors not only have an aggressive odor, but could also cause damage to vegetation, wildlife, and other aspects of the external environment, creating, in addition, a risk to health. Authorities in many countries, including the United States and Western Europe, have imposed increasingly narrow tolerances to discharge such vapors into the atmosphere.

U.S. Patent No. 5,425,806, recently issued to Rheox Inc., the assignee here, describes a liquid rheological composition containing an associative thickener and water wherein butyl carbitol has been replaced with a surfactant to form the pourable liquid addictive composition. The specification of US Patent No. 5,137,571, recently issued to Rohm & Haas Corp., exhibits some understanding of the environmental problems that associative fluid compositions can cause. Nevertheless, the patent continues with the practice of mixing a solid polymer in a medium liquid medium to form a pourable liquid composition. The patent describes the use of cyclodextrin starch derivatives to suppress the viscosity of an associative thickener in water and create a product of liquid composition. Cyclodextrin is absorbed in the hydrophobic groupings of associative thickeners.

US Patent No. 4,722,962, issued to DeSoto Inc., refers to nonionic surfactants, relative to associative thickeners, but teaches the reaction of such surfactants in the thickener polymer to form a portion of the final polyurethane. U.S. Patent No. 5,109,061 discloses a surfactant composition comprising a polyurethane or a water soluble polyurea dispersed in a surfactant. The composition is prepared by reacting an aliphatic or aromatic polyisocyanate with a polyol or polyamide in the presence of a surfactant, broadly defined as anionic, nonionic, ampholytic, surtrionic and cationic surfactants. The composition products are disclosed as being suitable for the preparation of molded or formed articles such as toys for bath tubs. U.S. Patent No. 5,270,378 shows surfactants and ariciclic compositions (such as graphic systems, including printing plates and sprayable polymerizable systems) containing these surfactants. In addition, the compositions comprise organic solvents.

US Patent No. 4,432,881 discloses thickening agents useful for drilling mud and fluid fragmentation formulations containing polyacrylamide dispersible in water and other polymers containing pendant hydrophobic groups, as well as cationic and nonionic surfactants, dispersed in a medium or solution watery The hydrophobic groups of the polymer are described as solvated by the surfactant in such a way that the thickening agent forms a solution in water, when the two components are stirred with deionized water in a period of time.

Australian Patent No. 515,783, which has no counterpart in the United States, discloses a concentrated thickener composition, which is a mixture of two thickeners, one, a non-ionic polyurethane and the other, an inert non-aqueous organic diluent, surfactant and coespesant, and from 0 to 65% by weight of water. Co-surfactant surfactant is used to increase the viscosity of the print or etch paste, in which the concentrate is dispersed. The thickener composition is described as a clear concentrate, and is contrasted with powder thickeners, which require subsequent further dilution. The clear concentrates are reported to have low manageable viscosity.

Object of the invention Rheox, Inc., the assignee of the present invention, sells synthetic polymers with 100% active spin, associative polyurethane powder thickeners. Along with the obvious savings that are made in the shipping of a 100% active rheological additive, such products have the additional advantage of being VOC-free. However, there are considerable difficulties in dispersing these solid synthetic polymeric thickeners directly in water or formulations of latex paints. When dispersed directly in latex, for example, there is an "irregular wetting" of the product, which results in the formation of lumps or globules whose core or center is still the dry polymer powder. This problem can be partially terminated in latex paints by either adding the additive to the "grinding" of the paint, or by first dispersing the additive into ethylene glycol and directly adding this mixture to the "precipitate" of the paint. . Unfortunately, this second option negates what is one of the greatest technological advantages of this product line, that is, the fact that the additives are free of VOC, because the glycols are not commonly present in the formulations of VOC free paintings. The addition of associative thickeners in an aqueous system that already contains surfactants, or with the simultaneous separate addition of surfactants and thickeners, has not remedied the known defects described above. A "superdispersible" solid product, which can be added directly to the paint, would fill an important need in the market.

Accordingly, it is the object of the present invention to solve or substantially alleviate the problems created by synthetic polymeric thickeners in thickener compositions for aqueous systems. It is therefore a more specific objective of the present invention to provide a mixture of a surfactant and an associative thickener as a substantially anhydrous composition which is useful for increasing the viscosity of a water-based system in an efficient and improved manner, more easily and without the environmental problems associated with liquid products containing dispersible organic solvents.

It is another object of the invention to provide a thickener mixture containing a solid synthetic polymeric thickener and defined surfactants which improve the dispersibility of the polymer in aqueous systems where it is used to provide rheological properties.

Detailed description of the invention.

The substantially anhydrous thickener composition of This invention is a mixture comprising: (a) From approximately 50 to 80% of a solid synthetic polymeric thickener including, for example, associative polyurethane thickeners; and (b) From approximately 15 to 50% of one or more anionic, cationic and nonionic surfactants.

The relative amounts of each of the foregoing chemicals in the thickener composition can vary over wide ranges, with an effective range of about 50-85% by weight of the polymeric thickener compound to 15-50% by weight of the surfactant being preferred and being a surfactant amount of about 30% most preferred. The percentages by weight are in relation to the two materials. It is understood that the solid term includes powder and powder type. It is preferred that both the polymeric thickeners and the surfactant used are in solid or powder form. It is also understood that additional additives can be added to the thickener composition in small amounts compared to those currently commonly used, preferably less than 30% of the amount of the surfactant used. Other ingredients known in the art other than water can be added to the inventive thickener compositions and include inorganic salts, solid and liquid fillers, chelating agents, regulating agents, clays, pH adjusting agents, neutralization chemicals, and the like. The composition results in a product that can be easily dispersed in latex paints, sealants, inks, resins and coating compositions.

The removal of water from the inventive composition reduces the risks of bacterial and fungal contamination of the product, and systems in which it is used, and reduces or eliminates the need for biocidal additives. In addition, water causes such compositions to become slippery and sticky, and less easy to handle and disperse. Substantially anhydrous means less than about 0.1-0.2% water by weight of the total composition.

Synthetic polymeric thickeners of all types previously discussed are useful for the invention. Particularly preferred are commercial polyurethane thickeners sold by Rheox Inc. under the trade names Rheolato 204, 205 and 208 and similar solids or powder thickeners sold, for example, by Rohm & Hass Company, Union Carbide Corporation, BASF Corporation, Hoechst (Germany) and Bayer GmbH.

The type of surfactants used in this invention are anionic, cationic and nonionic surfactants of the type described below, which at room temperature, exist in solid, semi-solid or liquid form. In a preferred embodiment, the surfactant used is made powder by grinding, spraying or a similar process: A. Anionic surfactants are characterized by having an amphipathic molecular structure composed of groups with opposite solubility tendencies, typically an oil-soluble hydrocarbon chain and a water-soluble ionic group. The presence of two structurally unequal groups within a single molecule is the most fundamental characteristic of the anionic surfactants. Such surfactants generally carry a negative charge in the hydrophilic portion of the surfactant. The actual behavior of the surfactant, ie the activity of the surfactant molecule, is determined inter alia by coating the individual groups, the solubility properties of the entire molecule, its relative size, and the location of the hydrophilic groups within the surfactant molecule.

The anionic surfactants useful in this invention are the surfactants characterized as having carboxylates, sulfonates, sulfates, or phosphates as their solubilizing, hydrophilic group. These groups are preferably combined with a hydrophobe with carbon chain (8-16 carbons is the most preferred) for better surfactant properties.

Representative for use with associative thickeners in the invention anionic surfactants include sulfonic acids, sulfonates, sulfates, alkyl ether sulfates, alkyl sulfosuccinates and sulfosuccinamates, phosphate esters, carboxylated alcohol ethoxylates and sodium, lithium, potassium , and ammonium of the aforementioned surfactants. Particularly preferred are: sulfates, sulphonates and sulfosuccinates including their salts. Commercial products useful in the invention include Aereosol AY-B, an 85:15 mixture of sodium diammon sulfosuccinate and sodium benzoate and Monawet MB-100, a diisobutyl sodium sulfosuccinate.

B. Nonionic surfactants do not carry discrete charge when dissolved in aqueous media. Solubilizing groups in this type of surfactant are usually ethylene oxide chains and hydroxyl groups. Hydrophilicity in nonionic surfactants is provided by linking hydrogen with water molecules. Oxygen atoms and hydroxyl groups easily form strong bonds of hydrogen, while groups of esters less easily form hydrogen bonds. Hydrogen bonds provide solubilization in neutral and alkaline media. * In strongly acidic environments, oxygen atoms are protonated, providing a quasi-cationic character. Each atom of oxygen makes a small contribution to the solubility of water. Therefore, more than one oxygen atom is needed to solubilize a nonionic surfactant in water. The nonionic surfactants are compatible with ionic and amphoteric surfactants. Nonionic surfactants include ethoxylated alkylphenols / alcohols / ami-nas / fatty acid / and / or amides, amine oxides, fatty acid esters, polysiloxanes derivatives, sucrose and glucose esters and sorbitan derivatives.

Particularly effective nonionic solid surfactants useful in the present invention are: ethoxylated alkyl phenols. C. Cationic surfactants generally carry a positive charge on the hydrophilic portion of the surfactant, usually on a nitrogen atom in the form of a quaternary ammonium compound with a group of 12-24 carbon atoms attached to the nitrogen. Cationic surfactants are mainly used as textile softeners, corrosion inhibitors, germicides and ingredients in personal care products. The cationic surfactants also include fatty amines, which include ethoxylated fatty amines, fatty imidazolines and amine oxides. The quaternary compounds include dihydrogenated tallow ammonium chloride with methyl benzyl, dimethyl ammonium chloride dicoco, tallow ammonium chloride dihydrogenated with dimethyl. Particularly effective surfactants include: EMCOL CC-9, a polypropoxy quaternary ammonium chloride. There are a number of ways to prepare the anhydrous thickener composition of the inventiveness. The thickener composition of the present invention is more preferably prepared by the addition of the thickening polymer to the surfactant and mixing the described chemicals in an apparatus useful for the mixing of chemicals such as a PK mixer. The composition can also be made by adding the surfactant at various stages in the polymer thickener manufacture including during the subsequent stages of its polymerization. The surfactant can also be added to the polymer thickener in solution and the solution dried to form a solid powder. In some cases, the use of a liquid surfactant may result in a liquid thickener composition. The mixture of the above chemicals can also be achieved using machinery similar to the one currently used to prepare solid products. While the relative amounts may vary, in general, the synthetic thickener will normally create more than 50% of the amount of the thickener composition or mixture. The relative amounts of the polymer and surfactant can effectively vary over a wide range by producing compositions according to the invention under economic conditions, to a certain extent, dictating the amount of the surfactant used. A preferred range of the relative amounts in the inventive composition is from about 60-85% of the associative thickener polymer, to about 15-40% of the surfactant. The preferred amount is that amount necessary to impart rapid dissolution of the water in the thickening polymer.

The use of the thickener composition of the invention is similar to the use of current commercial solid, synthetic polymers, and in general does not require special arrangements or apparatuses when such compositions are incorporated into aqueous systems. Typical levels of use are from 0.25% to 20% of the thickener mixture composition to the system, the percentage being based on the system to be thickened, with a range of 0.25% to 3.0-4.0% most preferred. The thickener composition can easily be mixed in an aqueous system using conventional mixing equipment, such as sand mills, medium and high speed dispersion machinery, blade or blade mixers, stone mills, ball mills, and mixing equipment Similary. Substantially less time and effort will be necessary to obtain an effective dispersion compared to that of today's solid thickeners. In a preferred embodiment, grinding or mixing a pulverized solid surfactant of the aforementioned type with solid pulverized polymeric thickeners results in a product that is easily dispersed in water or latex. This mixing composition can be added directly to a master batch of paint (with or without water) using appropriate mixers or common devices found in most manufacturers' plants. As an alternative, the dry composition of the invention can be added to the portion of the paint formula at a level of 10-80% solids, mixed in a solution and added as a liquid to the remainder of the formula. the painting. None of these stages of thickening leads to a loss of efficiency.

The following examples are illustrations designed to assist those skilled in the art in practicing the present invention, but are not intended to limit the invention. Changes can be made without departing from the spirit of the invention. The various chemicals used in the examples were commercially obtained materials.

E J E P L O S Example 1 This example is used to show the effectiveness of the surfactants to aid in the dispersion and solubilization of associative thickeners of solid polyurethanes sprayed in water. A number of associative polyurethane thickeners were prepared using standard polymerization techniques known in the art. Three such powder polymers, designated polymers A, B and C, had the following compositions: Polymer A The polyurethane reaction product of poly (ethylene glycol), an aliphatic diisocyanate, a mixture of fatty diamines, and a mixture of fatty alcohols.

Polymer B The polyurethane reaction product of poly (ethylene glycol), an aliphatic diisocyanate, a single fatty diamine, and a mixture of fatty alcohols.

Polymer C The polyurethane reaction product of poly (ethylene glycol), a branched chain aliphatic diisocyanate, a single fatty diamine, and a fatty amine.

The polymers described above were then mixed for about 60 minutes with a pulverized anionic surfactant. An accepted / rejected screening analysis was developed to determine if a particular polymer / surfactant combination could easily be dispersed or solubilized in a pure water system, such a system being generally representative of an aqueous system. 90gr of deionized water was weighed into an 8-ounce container and 10g of the sample was weighed into a paper cup, comprising 10 parts of the polymer and 3 parts of the surfactant. The container containing the water was placed in a laboratory mixer equipped with a blade propeller, with the blades placed approximately 1.27 cm (0.5 inches) from the bottom of the container. The mixer was set at 250 rpm, the sample was added to the water all at once and mixed for a total of 5 minutes. The sample was removed or removed from the mixer, and evaluated as accepted or rejected.

Accepted - Liquid, homogeneous, soft, light white to creamy No dry powder on the surface of the water, vessel sides or shafts and blades of the mixer - No lumps or gel bubbles Rejected - Gelatinous clumps of adhered polymer to the blades of the mixer, lumps of polymer or gel pockets through the water, dry powder on the surface of the water or the sides of the container.

When it was found that a particular polymer / surfactant combination passed the aforementioned test, it was then dispersed in a standard batch of paint. The sieving analysis of the paint consisted of adding the appropriate amount of the anhydrous thickener composition of a standard half-pint sample batch, first, a purely aqueous system, and second, a commercial latex paint.

The system and thickener composition was then mixed for 10 minutes with a Cowles disperser. The initial and after-night viscosities of both the ICI and Stomer systems were measured.

Run to Determine the Lower Interval A test was run to determine a lower limit of the amount of the surfactant necessary for the invention. This test constituted a stepwise study of the amount of the surfactant / solubilizer in the final product to determine whether the amount of the surfactant could decrease without affecting the dispersibility and other properties of the present invention. The surfactant used in this test was Aereosol AY-B, an anionic diamyl sulfosuccinate, with Polymer A. The results of the test presented in Table 1 give the results of the Accepted / Rejected test in a purely aqueous system together with the Initial viscosity results and after one night in the latex paint system described in Table 3.

Table 1 The results described above show that a lower limit of about 15% of the surfactant is necessary to achieve the beneficial effects of the invention.

The above results also show that, once the lower limit of the surfactant of the invention is reached, the increase of the amount of the surfactant in the product does not detract the performance of the associative thickener in a water-based latex paint.

Tests performed with various surfactants and polymers.

The tests were then performed, using the techniques described above using an anhydrous mixture of polymers A B and C and several additional surfactants in the form of powder with a load of 23% with the result of the accepted / rejected test in a purely aqueous system given in table 2 and in a latex paint in Table 4.

Table 2 * Aereosol AY-B: Sodium diaminosulfosuccinate; CYTEC, Inc.

Monawet MB-100: Sodium diisobutyl sulfosuccinate; Mona Industries, Inc.

Witconate LX: Sodium alkylaryl sulfonate; Witco Corp.

Nacconal 90G: Alkylbenzene sulfonate Linear; Stepan Co.

Witconate K: Dodecylbenzene sulfonate, sodium salt, Witco Corp.

Dowfax 3B2-D: Benzene sulphonic acid of Decil (sulfophenoxy), disodium salt; Dow Quemical Co.

XU 40333.00: Derivatives of 1, 1-oxybis-tetrapropylene, Benzene, sodium salt, Dow Chemical Co.

Example 3 This example demonstrates the ability of the thickener composition of the invention to thicken latex paints. The paint formula is given in Table 3 shown below.

Table 3 5 Scattered at high speed for 15 min. and added: The viscosities of the Stormer and ICI samples are reported in Table 4.

Table 4 See Table 2 for the chemical description of the above surfactants.

The above results demonstrate the ability of various surfactants to aid in the dispersibility of powder solid associative thickener compositions, for water-based systems including latex paints. The fact that the initial viscosities of the paint, taken an hour after the thickener was incorporated into the paint system, They are. equal to the viscosities of the paint after a night, demonstrates the ability of the surfactants to immediately disperse and solubilize the associative thickener. The above results also show that the surfactant does not detract from the thickener power of the additive, because the polymer / surfactant samples are equal in viscosity to their polymer / butyl carbitol / water counterparts. 4 An experiment was conducted to prepare a mixture of a polymeric thickener and a surfactant in solution with water, and then dried, to examine the dry product for ease of dispersibility. 150 g of a mixture of Polymer A and Aereosol AY-40 surfactant, a 40% activity of diamil sodium sulfosuccinate obtained from Cytec, Inc., was dried overnight at 55 ° C in a vacuum oven. The dried leaf was crumbled and ground with liquid N2 by a Brinkman mill without a sieve.

Fine particles of the material were placed in HzO at 20% polymer concentration and the dried material was completely dispersed quickly and easily.

A second method of mixing a liquid surfactant with the dry polymer product involved dispersing both the polymer and the surfactant in an appropriate solvent and, after mixing, removing the solvent to leave an anhydrous, solid product. 50 g of Polymer A and 15 g of the surfactant were added to 150 g of methanol, mixed, and dried at 0 vacuum; the polymer / dry surfactant was then milled by a Brinkman mill to give a dry powder product. The dried product was placed through the Accepted / Rejected water test, and was accepted, and the viscosities of the paint in the paint formula of Table 3 are given below in Table 5: Table 5 * Triton X-100: Polyether alkylaryl alcohol, a non-ionic surfactant. Union Carbide Chemicals and Plastics Co .; Emcol CC-9: polypropoxy quaternary ammonium chloride, a cationic surfactant; Witco Corp.

The above results demonstrate the ability to use liquid surfactants in the present invention and then remove any liquid or solvent used to make the product give us a dry sprayed product. The above results also demonstrate that the fact that the product is made in this manner does not detract from its effectiveness in the thickening of water-based latex paints.

The above description and examples have been disclosed only to illustrate the invention and are not intended to be limiting. Because modifications to the disclosed embodiments embodying the spirit or substance of the invention can occur to persons skilled in the art, the invention should be constructed to include everything within the scope of the appended claims and their equivalents.

Claims (28)

1. A substantially anhydrous thickener composition comprising: a) from about 50 to 80% by weight of a synthetic solid polymeric thickener; Y, b) from about 15 to 50% by weight of one or more surfactants selected from the group consisting of anionic, cationic and nonionic surfactants.

2. The composition according to claim 1, wherein one or more of the surfactants is a solid.

3. The composition according to claim 1, wherein the synthetic polymeric thickener is selected from the group consisting of polyurethanes, polyesters, polyester urethanes, polyether alpha olefins, and polyether polyols.

4. The composition according to claim 1, wherein the synthetic solid polymeric thickener is a polyurethane.

5. The composition according to claim 4, wherein the polyurethane is characterized by hydrophobic groups interconnected with hydrophilic groups, and has a molecular weight of 2,500 or greater.

6. The composition according to claim 1, wherein the synthetic polymeric thickener is a polyoxyalkylene compound with a hydrogen-containing initiator capped with an alpha-olefin oxide group.

7. The composition according to claim 1, wherein the amount of the surfactant in the composition is less than 30%.

8. The composition according to claim 1, wherein one or more of the surfactants is an anionic surfactant.

9. The composition according to claim 8, wherein the anionic surfactant is selected from the group consisting of alkyl ethoxylated phenols, ethoxylated alcohols, and polyglycols.

The composition according to claim 1, comprising one or more additional components selected from the group consisting of fillers, clays, neutralizing chemicals and regulating agents.

11. A substantially anhydrous solid thickener composition comprising: a) from about 50 to 85% by weight of a solid associative polyurethane thickener, b) from about 15 to 50% by weight of one or more anionic surfactants in powder form.

12. The composition according to claim 11, wherein the associative polyurethane thickener is characterized by hydrophobic groups interconnected by hydrophilic groups, and has a molecular weight of 2,500 or greater.

13. The composition according to claim 11, wherein the amount of the surfactant in the composition is less than 25%.

14. The composition according to claim 11, wherein the anionic surfactant is selected from the group consisting of dialkyl sulfosuccinates, alkyl sulfates, alpha olefin sulphonates and sulfates of ethoxylated alcohols.

15. The composition according to claim 11, comprising one or more additional components selected from the group consisting of fillers, clays, neutralizing chemicals and regulating agents.

16. An improved method for increasing the viscosity and leveling characteristics of an aqueous system comprising mixing within the aqueous system from about 0.25% to 20% by weight of a substantially anhydrous thickener composition comprising: a) from about 50 to 85% by weight of a synthetic solid polymeric thickener; Y, b) from about 15 to 80% by weight of one or more surfactants selected from the group consisting of anionic, cationic and nonionic surfactants.

17. The method according to claim 16, wherein the aqueous system is latex paint.

18. The method according to claim 16, wherein the synthetic polymeric thickener is an associative thickener.

19. The method according to claim 16, wherein the associative thickener is a polyurethane.

20. The method according to claim 18, wherein the associative thickener is a polyoxyalkene compound, initiated with an initiator containing active hydrogen and topped with alpha olefin oxide groups.

The method according to claim 16, wherein one or more of the surfactants is an anionic surfactant.

22. The method according to claim 16, wherein the anionic surfactant is selected from the group consisting of dialkyl sulfosuccinates, alkyl sulfates, alpha olefin sulphonates, and sulfates of ethoxylated alcohols.

23. An improved method for increasing the viscosity and leveling characteristics of an aqueous system comprising mixing within the aqueous system, from about 0.25% to 20% by weight of a substantially anhydrous thickener composition comprising: a) from about 50 to 85% by weight of an associative solid polyurethane thickener; Y, b) from about 15 to 50% by weight of one or more surfactants selected from the group consisting of anionic, cationic and nonionic surfactants.

24. The method according to claim 23, wherein one or more of the surfactants is a solid.

25. The method according to claim 24, wherein the solid surfactant is in powder form.

26. The method according to claim 23, wherein the aqueous system is latex paint.

27. The method according to claim 24, wherein one or more of the solid surfactants is an anionic surfactant.

28. The method according to claim 27, wherein the solid anionic surfactant is selected from the group consisting of dialkyl sulfosuccinates, alkyl sulphates, alpha olefin sulphonates and sulfates of ethoxylated alcohols. EXTRACT An improved thickener composition for an aqueous system including latex paints and coatings is disclosed. The substantially anhydrous composition comprises in specific ratios a solid thickener polymer, and one or more surfactants. The solid thickener polymer includes associative thickeners. The associative thickener polymers include polyurethanes, polyesters, polyacrylamides, modified hydroxyethyl celluloses, soluble alkali emulsions and other chemicals. Specific surfactants used include dialkyl sulfosuccinates, alkyl sulfates, alpha olefin sulphonates, and sulfates of ethoxylated alcohols.